Facebook, the world's most popular online social network, has announced that it is redesigning its privacy protections in response to mounting pressure to better secure the personal data that is exchanged among its nearly 500 million members.

The issue has come to a head in recent months amid concern that Facebook makes it possible for marketers and advertisers -- as well as Internet stalkers and cyber-criminals -- to gain a wealth of information about users without their knowledge.

Critics include privacy and consumer groups as well as U.S. lawmakers and the European Union. But the criticism has been proliferating among Facebook users themselves since December when the California-based company started changing the rules about what information it shares with advertisers and marketers -- a move apparently aimed at increasing its revenues.

"The No. 1 thing that we've heard is that there just needs to be simpler ways to control your information. We agree," Facebook Chief Executive Mark Zuckerberg announced at a press conference May 26 in California. "So today we started rolling out three new things to address this. First, we have built one simple master control that you can use to set who can see all of the content you share on Facebook. We haven't removed anything in this update. We've just added a simple master switch to control all of your content at once."

Zuckerberg says the changes will allow users to block all third parties from accessing their information without their explicit permission. He says it also will make less information available in its user directory. Finally, he says the number of settings required to make all of a user's information private will be reduced from nearly 50 to less than 15.

Still, Zuckerberg says Facebook's default settings will continue to make it relatively easy for users to obtain information about each other, as the company walks a delicate line between protecting privacy rights and promoting social networking.

Labyrinth Of Settings

Users complain that Facebook's current system allows the company to automatically share personal profile information with advertisers and others on the Internet.

To stop that information from being accessed by people or companies outside of their circle of friends, Facebook users must be astute enough to change the default settings on their personal account. In essence, in the current setup, Facebook users must specifically instruct the firm not to allow their information to be shared, and they must circumnavigate a labyrinth of settings to do so.

Sabrina Drevsfeltt, a regular Facebook user from Europe, says the current system is too complicated for users to be sure they are protecting their privacy.

"I try to close as much of my information as I can, but I think it is really complicated to know which information is going out and which is not," she said. "I don't feel very good about it."

In New York, Facebook user Margot Silver told Reuters she feels she must be careful about what photos or information she posts to her Facebook profile because she is unsure about what will remain.

"I have been hearing a lot about it -- how all our information is open to the public. I don't put too much on my page -- too many personal things -- so I'm not super worried about it," Silver said. "But I do think it is a concern and I think it's something that should be addressed because it is not meant to be open to everyone."

Introduced Gradually

Zuckerberg says Facebook's redesigned privacy settings will be introduced gradually during the weeks ahead. It remains unclear whether those voluntary changes will be enough to prevent regulators from launching a full examination into whether Facebook is giving users sufficient control over the privacy of their personal data.

But the revamp is being welcomed by some.

Lance Ulanoff, the editor in chief of "PC Magazine," says it is the criticism from Facebook users that has spurred the company to rethink the way it will allow personal information to be shared or used for marketing.

"These were big and necessary changes. Facebook had to do something. They were under fire for their privacy settings," Ulanoff says. "They had made a lot of changes last year in December. But now they feel like they went too far, too fast. They spent a lot of time listening to users and admit that they made a lot of mistakes."

Facebook is a private company and does not disclose financial data. But analysts estimate its 2009 revenue at $500 million to $650 million -- primarily from selling online advertisements targeted at users based on their activity and profile information on Facebook.